This invention relates to rotary engines and, more particularly, to seal assemblies for rotary engines.
Prior art of possible relevance includes the following U.S. patents: U.S. Pat. No. 3,046,069 to Schmidt, issued July 24, 1962; U.S. Pat. No. 3,127,095 to Froede, issued Mar. 31, 1964; U.S. Pat. No. 3,152,552 to Frenzel, issued Oct. 13, 1964; U.S. Pat. No. 3,176,609 to Maurhoff, issued Apr. 6, 1965; U.S. Pat. No. 3,193,188 to Bentele, issued July 6, 1965; U.S. Pat. No. 3,281,064 to Springer, issued Oct. 25, 1966; U.S. Pat. No. 3,400,691 to Jones, issued Sept. 10, 1968; U.S. Pat. No. 3,556,695 to Yamamoto, issued July 19, 1971; U.S. Pat. No. 3,667,877 to Lamm, issued June 6, 1972; U.S. Pat. No. 3,712,767 to Beutter, issued Jan. 23, 1973; U.S. Pat. No. 3,745,630 to Bensinger, issued July 17, 1973.
While the operating principles of various types of rotary engines have long been known, to date they have not met with appreciable commercial acceptance. One significant drawback to the commercialization of such engines resides in the problems posed by the seals carried by the rotors employed.
Problems with seals can be divided into many areas and the instant invention is concerned with the overcoming of two problems typically encountered with seals.
A first problem is that of obtaining good sealing contact between the ends of an apex seal in a rotary engine. Typically, the total length of an apex seal is made somewhat less than the width of the rotor to allow for expansion of the seal due to high operating pressures and to preclude the ends of such seals from causing unnecessary wear on the sides of the engine operating chamber. In typical constructions, a gap will always exist with the consequence that some leakage will occur at the ends of an apex seal with the ultimate consequence of reduced operating efficiency.
Another problem encountered with apex seals is that frequently the same require a multiplicity of parts. Frequently, each seal will be comprised of a main sealing bar provided with a wedge at one, or both ends. In addition, one or more springs are employed to bias the sealing bar and the wedge into sealing engagement with the walls of the operating chamber. Not infrequently, a minimum of four parts are employed. Given a typical rotary engine of the so-called "Wankel" variety, there will be at least twelve parts required for apex seals.
Installation of the seals in such an engine becomes a nightmare since, typically, the springs will be pushing the remaining parts out of the seal receiving grooves. Frequently, the prior art has resorted to the use of taping such parts in place to overcome the aforementioned problem. However, frequently, a mechanic or an assembler on an assembly line will forget to remove such tape with the result of operational difficulties. In addition, because of the multiplicity of parts, frequently, one or more parts may be omitted through inadvertence, again causing operational difficulties.